Decouple rtengine/ from rtgui/edit.h

rtgui/mydiagonalcurve.cc

@@ -16,11 +16,16 @@
  *  You should have received a copy of the GNU General Public License
  *  along with RawTherapee.  If not, see <http://www.gnu.org/licenses/>.
  */
-#include "mydiagonalcurve.h"
-#include "../rtengine/curves.h"
 #include <cstring>
+
 #include <gdkmm/types.h>
 
+#include "mydiagonalcurve.h"
+
+#include "edit.h"
+
+#include "../rtengine/curves.h"
+
 MyDiagonalCurve::MyDiagonalCurve () :
     MyCurve(),
     closest_point(0),